Electron microscopic study of the snout muscle spindles of the mole following denervation

The authors examined electron microscopically the daily effects of the muscle spindles of the mole snout muscles following unilateral facial neurotomy. The denervated muscle spindles show first a degenerative sign of the sensory end bulb 1 day after the operation and later a degenerative sign of the intrafusal muscle fibers one week after the operation. The muscle spindles on the untreated side show first a degenerative sign of the intrafusal muscle fibers 2 weeks after the operation and later a degenerative sign of the sensory end bulb 20 days after the operation. 40 to 90 days after the operation, the spindles on both sides show the same degenerative signs, the intrafusal muscle fibers having become much thinner than the control.